a/Ta có:\(1-\dfrac{2006}{2007}=\dfrac{1}{2007}\)
\(1-\dfrac{2008}{2009}=\dfrac{1}{2009}\)
Do \(\dfrac{1}{2007}>\dfrac{1}{2009}\) nên \(\dfrac{2006}{2007}< \dfrac{2008}{2009}\)
b/Ta có:
\(1-\dfrac{a+5}{a+6}=\dfrac{a+6-\left(a+5\right)}{a+6}=\dfrac{a+6-a-5}{a+6}=\dfrac{1}{a+6}\)
\(1-\dfrac{a+1}{a+2}=\dfrac{a+2-\left(a+1\right)}{a+2}=\dfrac{1}{a+2}\)
Do \(\dfrac{1}{a+6}< \dfrac{1}{a+2}\) nên \(\dfrac{a+5}{a+6}>\dfrac{a+1}{a+2}\)
#kễnh

a) Ta có:

\(1-\frac{2005}{2006}=\frac{1}{2006}\)

\(1-\frac{2006}{2007}=\frac{1}{2007}\)

Vì \(\frac{1}{2006}>\frac{1}{2007}\)nên \(\frac{2005}{2006}>\frac{2006}{2007}\)

b) Ta có:

\(\frac{2008}{2007}-1=\frac{1}{2007}\)

\(\frac{2007}{2006}-1=\frac{1}{2006}\)

Vì \(\frac{1}{2006}>\frac{1}{2007}\)nên \(\frac{2008}{2007}< \frac{2007}{2006}\)

a, \(\frac{2005}{2006}v\text{à}\frac{2006}{2007}\)= \(\frac{2005\cdot2007}{2006\cdot2007}\)và \(\frac{2006\cdot2006}{2007\cdot2006}\)

= \(\frac{4024035}{4026042}\)< \(\frac{4024036}{4026042}\)

b, \(\frac{2008}{2007}v\text{à}\frac{2007}{2006}\)= \(\frac{2008\cdot2006}{2007\cdot2006}v\text{à}\frac{2007\cdot2007}{2006\cdot2007}\)

=\(\frac{4028048}{4026042}\)< \(\frac{4028049}{4026042}\)

a)A = B

b)A>B

a. kết quả = 401/402

b. Ta có: 1-2004/2009=5/2009     ,        1--2005/2010=5/2010 . Vì 5/2009  > 5/2010 nên 2004/2009 < 2005/2010.

Đấy phần b. mk ko quy đồng nha! 

Nhớ Tích cho mk đấy

thế phần a chỉ cần làm như vậy thôi à pạn

Alo tuổi lìn sánh vai

Bài 2: 

a: \(5^{2008}+5^{2007}+5^{2006}\)

\(=5^{2006}\left(5^2+5+1\right)=5^{2006}\cdot31⋮31\)

b: \(8^8+2^{20}\)

\(=2^{24}+2^{20}\)

\(=2^{20}\left(2^4+1\right)=2^{20}\cdot17⋮17\)